The present invention relates to encased motors of the type having means for dissipating the heat generated by the stator coils, and in particular, it relates to an encased motor wherein those means comprise a gas mixture having good heat conducting qualities sealed within the can.
In canned motors according to the prior art, it is common to completely fill the stator enclosure of the motor with a potting compound comprising a resin having excellent heat conductivity. The potting compound conducts the heat produced by the stator coils to the surface of the casing, where the heat is dissipated. Although resins are excellent from the standpoint of heat dissipation, they have a number of disadvantages. First, they are costly. Second, they greatly increase the weight of the encased motor. The third and the biggest disadvantage is that they expand due to heating when the motor is overloaded, and this expansion may produce warping and other physical distortion of the walls of the casing. Accordingly, this means of heat dissipation is not satisfactory.